SN54AS877, SN74AS877 8-BIT UNIVERSAL TRANSCEIVER PORT CONTROLLERS

SDAS234 - D2661, DECEMBER 1982 - REVISED AUGUST 1985

features

Package Options Include Plastic Small Outline Packages, Both Plastic and Ceramic Chip Carriers, and Standard Plastic and Ceramic 300-mil DIPs
Buffered 3-State Outputs Drive Bus Lines Directly
Cascaded to n-Bits
Eight Selectable Transceiver/Port Functions: A to B or B to A Register to A or Register to B Shifted to A or Shifted to B Off-Line Shifts (A and B Ports in High-Impedance State) Register Clear
Particularly Suitable for Use in Signature Analysis Circuitry
Serial Register Provides: Parallel Storage of Either A or B Input Data Serial Transmission of Data from Either A or B Port
Dependable Texas Instruments Quality and Reliability

description

The 'AS877 features two 8-bit I/O ports (A1-A8 and B1-B8), an8-bit parallel-load, serial-in, parallel-out shift register, andcontrol logic. With these features, this device is capable ofperforming eight selectable transceiver or port functions, dependingon the state of the three select lines S0, S1, and S2. Thesefunctions include: transferring data from port A to port B or viceversa (i.e., the transceiver function), transferring data from theregister to either port,

serial shifting data to either port, performing off-line shifts(with A and B ports in high-impedance state), and clearing theregister. Synchronous parallel loading of the internal register canbe accomplished from either port on the positive transition of theclock while serially shifting data in via the SERIN input. The 'AS877is ideally suited for applications needing signature-analysiscircuitry to enhance system verification and/or fault analysis. Allserial data is shifted right. All outputs are buffer-type outputsdesigned specifically to drive bus lines directly and all are 3-stateexcept for Q8, which is a totem-pole output.

The SN54AS877 is characterized for operation over the fullmilitary temperature range of -55°C to 125°C. The SN74AS877is characterized for operation from 0°C to 70°C.

n = level Of Q_n(n = 1, 2 . . . 8) established onmost recent transition of CLK. Q1 thru Q8 are the shift registeroutputs; only Q8 is available externally. The double inversions that take place as data travels from port to port areignored in this table.

Title: 8-BIT UNIVERSAL TRANSCEIVER PORT CONTROLLERS
Product Family: UNIVERSAL BUS TRANSCEIVERS (UBTS)
Device Functionality: 8-BIT UNIVERSAL TRANSCEIVER PORT CONTROLLERS
Orderable Devices: SN74AS877DW, SN74AS877NT

View the complete PDF datasheet: sdas234.pdf (141 K Bytes) (Requires Acrobat Reader 3.x)

View more information about generic part numbers:SN74AS877

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